Do the Cup Surface Properties Influence the Initial Stability?

This project tests the relationship between the acetabular cup surface characteristics and their initial stability by comparing uncemented (Trabecular Metal (TM) and Trilogy) and cemented polyethylene shells. We hypothesised that different surface properties of uncemented cups will influence the cup stability. Mounted directly onto host bone, TM and cemented cups were significantly more stable than Trilogy cups (P < 0.01), with minimal difference between TM and cemented cups (P > 0.1). On 100% graft bed, there was marginal difference between all three cup types (P > 0.1). Incremental cavitary and segmental defects resulted in reducing stability, with cemented cups being minimally more stable (P > 0.1). TM cups possess satisfactory initial stability in bone graft constructs. This study demonstrates that TM shells are marginally less stable than cemented cups in the absence of significant host bone contact.